Abstract: A portable auxiliary current source characterized by an overall configuration such that it is stable only in two positions, one of which is the desired operative position and the other of which is a position in which the source controls are inaccessible so that the source cannot be operated. The casing is prismatic in shape, characterized by a plurality of obtusely angled edges. In cross section, it is hexagonal with the base and the top wider than the other surfaces; and the center of gravity is very near the base so that the casing tends to tip toward one of those two positions but prefers the operative position. The casing rests in a cradle that provides handles for moving the source and that is also shaped so as to tip the source toward one of those two positions.